correct option is d) diamminetctraaquacobalt (III) chloride
First of all, the compound has complex positive part\( [Co(H_2O)_4(NH_3)_2]_{ 3+}\) therefore, according to IUPAC conventions, positive part will be named first. Secondly, in writing name of complex, ligands are named first in alphabetical order, irrespective of its charge, hence "ammine" will be written prior to "aqua